I(3,4,5,6)= Engines with cylinders in a line, often higher revving potential, good fuel economy, and without forced induction, yielding low horsepower.

V(6,8,10,12) = Engines with cylinders that are arranged in a V formation, often yielding torquey engines with low revs.

Flat(4,6) = Engines that have their cylinders horizontally opposed. Also known as the boxer engine. Has a low rumble, often yielding compact engine sizes.

W(12,16) = Engines with cylinders arranged in a W formation. Like the V engines, they often yield high torque using low revs.

Wankel Rotary (1,2 rotor piston) = engine that uses rotors instead of cylinders. Very smooth and high revving potential at a cost of bi-monthly lubrication, and crappy fuel economy. High horsepower at lower displacement. Very small and can be mounted deeper for a more balanced car.
Types of Alternative Transmissions:

There are many different clutches made by many different car manufacturers. Each car manufactor has clutches that feel very exlusive to that brand. Clutch feel can be classified by Resistance (heavy vs. light), Travel (long vs. Short), and Engagement points (high vs. low). These three characteristics make different clutches distinguishable. People who have driven many manual transmission cars in their life time can testify to theses differences of clutch feel throughout their many cars, and even comment on how it has affected their driving ability.

When first entering a new vehicle (by new, I mean new to you) you must find out the characteristics of the clutch first before you begin driving. The first test you perform is simply depress the clutch all the way to the floor and come back up. Do this several times to get the feel of how much resistance you are dealing with, and also the length of the clutch travel.

The second test you perform tells you where the engagment point, or where the clutch catches, is. This test will be referred to as the no-gas launch. This test is also a good drill for new manual drivers to get used to their car's engagement point. To execute this test you would:

1. Depress the clutch and turn on the engine.
2. With the clutch still depressed, shift into 1st or reverse.
3. Bring you clutch up slowly until your car starts moving.
4. memorize this location, because that is where your engagement point is.

I find that It is easy to memorize this engagement point by comparing its relative position to you brake pedal and also the floor. In my Z, the engagement is about 1 inch under the level of my brakes. On the other hand, my friend's Si's engagement point is about 2 inches off the ground. Once you get used to all the three aspects of your clutch, you will be more comfortable with your everyday driving.

1> You have already braked so much that your RPMs have dropped almost to idle and you are on the brink of lugging so you need to downshift.
2> You have not quite mastered the rev-matched downshift quite yet, but still want to get in the habit of downshifting before a turn.

The no rev-match downshift is pretty self explanatory but here are some pointers:

1> Make sure your revs are low enough to attempt to downshift without rev-matching. By low I mean from 1-1.5k.

2> When dowshifting, hold the clutch in for about one second for the RPMs to drop a little more.

3> Do not dump the clutch, rather bring it out slowly, like you would a normal launch.

4>ALWAYS finish your shifts BEFORE you turn.

Here are some example scnenarios:

A. You are traveling 30 miles in 3rd gear and approaching a 90 degree turn.
1. Start braking and wait for your rpms to drop.
2. Once your Rpms are around 1.5K clutch in and shift down to second.
3. Hold clutch in until RPMS drop to about 1k and let out.
4. Take the turn.

B. You are travelling 45 mph in 4th and you suddenly have to slow down to 30 because of a slow car.
1. Start breaking until your RPMs drop again to 1.5K
2. Again, once your Rpms are around 1.5K clutch in and shift down to Third.
3. Hold clutch in until RPMS drop to about 1k and let out.

Remember that Rev-match when your in doubt, but remember you do not always have to rev-match in certain situations.

Basically, think of coasting like a roller coaster. The roller coaster moves by applying a force or building up momentum at the beginning and then from that point forward, it's basically brought along with it's own momentum. No other force is applied to it. This is same with a car. When you coast, you basically are adding no gas. you are moving along with only the momentum of the car.

Added note from CaliforniaZX:
Coasting should always be done in gear. Do not coast to a red light in neutral. In contrary to beliefs, it does not save you gas but rather eats up more gas then coasting in gear. This is because when you are coasting in gear the wheels are running the engines and the fuel injectors are shut off. On the other hand, when you are coasting in neutral, your engine is using gas to keep the engine idling. Coasting in neutral is also dangerous because you do not have any control of your car because your drivetrain is discconnected. So for safety and economy sake, please coast in a high gear like 4th, 5th, or 6th when appropriate.

It should be noted that push-starting a stick should only be done in an emergency or when you cannot jump-start.

1. Hold down the clutch and shift into 2nd
2. Start pushing up to a brisk walk
3. Release the clutch quickly; as you do, turn the key to "on"
4. The car should come to life, at which put you should floor the clutch and rev a bit to keep the engine going
5. Don't turn the engine off until you've been driving for a bit.

Ok, i see alot of misinformed people here, and I would like to straighten it out.

Here are the basic terms of shifting:

Powershifting - Shifting with the gas floored, you need to be very fast, and skilled to do this. If you are, there is really no damage done to the drivetrain, if you only do it a few times, doing it all of the time, with a weak drivetrain can be hazardous. True drag racers that have fast cars also powershift, if they dont, they are giving up so much time trying to shift their cars, that they may even lose a few seconds off of their ET

Shifting without a clutch - Yes it is possible, and if you know how to do it, you are putting virturally no wear on the drivetrain

Double Clutching - When you take your car out of gear, let the clutch out in neutral, and press the clutch back in and go to the next gear. It is said to help lessen the wear of your cars syncros.

Heel to toe - used when you downshift for a sharp turn, you press on the brake with your toes, and are hitting the gas pedal with the heel of your shoe, reving it up to do your downshift... It is really good to accelerate through the turn.

These are the main ones, but they are many varities of all of them (like you can heel to toe double clutch, do double clutch downshifts, ect ect.)